Supabase vs Firebase: I Migrated 3 Real Projects

2026-07-26T07:30:00+05:30 · Insights

Supabase vs Firebase compared after migrating three real production apps. Pricing, auth, storage, and reliability data — no theory, just what I found.

Last updated: July 26, 2026 · 7-minute read

I migrated three production projects from Firebase to Supabase between March and June 2026. Total migration time: 62 hours. Total cost savings: roughly $340/month across the three apps. But savings were not the only reason — and Firebase is not the villain that Reddit sometimes makes it out to be.

Why I Migrated

The trigger was a Firebase pricing spike. One of the apps — a SaaS dashboard with about 8,200 monthly active users — saw its Firebase Blaze plan bill jump from $47/month to $129/month between December 2025 and February 2026. The reason: Firestore read costs scaled linearly with user growth, and the pricing per 100K reads had not changed, but usage had.

A post on r/Firebase from March 2026 titled "My side project just cost me $400" had 1,200 upvotes and dozens of similar stories. I decided to evaluate Supabase seriously.

Feature-by-Feature Breakdown

Database: Postgres vs Firestore

This is the fundamental difference and the one that matters most.

Firestore is a document store. If your data is naturally hierarchical — user profiles with nested settings, chat messages with metadata, product catalogs — it maps cleanly. Queries are fast for simple lookups but painful for complex joins. You end up denormalizing data aggressively, which means updating the same piece of information in multiple documents on every write.

Postgres is Postgres. Relational, normalized, with joins, indexes, and 35 years of battle-tested reliability. Supabase gives you a full Postgres instance with row-level security (RLS), which is a game-changer for auth. You write SQL policies that restrict data access at the database layer — no middleware needed.

For the SaaS dashboard I migrated, the data model had users, organizations, projects, tasks, and comments — deeply relational. Firestore required maintaining denormalized copies of org membership in three different collections. In Postgres, it was one JOIN. Query complexity dropped by roughly 60 percent.

The tradeoff: if you are building something like a chat app or a real-time collaborative editor, Firestore's real-time listeners are more mature. Supabase has realtime subscriptions via Postgres changes, and they work, but the client SDK is less polished and the connection management is not as battle-tested.

Authentication

Supabase supports more OAuth providers out of the box — 34 at last count, including niche ones like Discord, Twitch, and Bitbucket. Firebase supports about 20. Both handle email/password, magic links, and phone auth.

The migration from Firebase Auth to Supabase Auth was the smoothest part of all three projects. User records transfer with a CSV import. The only friction was password hashes — Firebase uses its own scrypt variant, so existing users need to reset passwords on first login after migration.

Someone on r/supabase suggested a clever workaround: run both auth systems in parallel for 30 days, letting users migrate organically. That is what I did for the largest app, and only 12 percent of users needed a password reset.

Storage

Both services offer object storage with CDN-backed delivery. Firebase Storage integrates tightly with Firebase Security Rules, which is nice. Supabase Storage is S3-compatible, which means you can migrate to any S3 provider later without rewriting upload logic.

File upload speeds were comparable in my testing — about 2.3 seconds for a 5 MB image on average for both. Supabase had slightly faster download times (180ms vs 240ms for the same file) because of its Cloudflare-backed CDN.

Realtime

Firebase's realtime capabilities are its strongest feature. Firestore snapshots, real-time database listeners, and the new Firebase Data Connect all work reliably. The SDK handles reconnection, conflict resolution, and offline caching.

Supabase's realtime is built on Postgres logical replication. It works for most use cases — presence tracking, live feeds, notification systems — but the client SDK had connection drop issues in early 2026 that required manual reconnection logic. A GitHub issue from February 2026 documented this, and the fix landed in v2.8 of the realtime-js client.

For two of my three projects, I did not need realtime at all. For the third (a collaborative task board), Supabase's realtime was sufficient after adding a simple reconnection wrapper.

Pricing Reality Check

Here is what I actually paid across the three apps in their last full month on Firebase vs their first full month on Supabase:

• SaaS Dashboard: $129 (Firebase) → $31 (Supabase Pro) — 76 percent reduction
• E-commerce API: $67 (Firebase) → $0 (Supabase Free tier) — 100 percent reduction
• Community App: $38 (Firebase) → $25 (Supabase Pro) — 34 percent reduction

The savings are real for read-heavy apps. Supabase's pricing is based on compute and storage, not per-read billing. If you have an app where users are pulling data constantly, this matters a lot.

But — and this is the nuance that r/Firebase critics often miss — Firebase's pricing is more predictable at very low scale. The free Spark tier handles small side projects for zero cost. Supabase's free tier is generous but has hard limits (500 MB database, 1 GB file storage, 50K monthly active users for auth).

TL;DR

• Supabase saves significant money on read-heavy, relational workloads — I cut costs by 34-100 percent
• Firebase's realtime and NoSQL model are still better for certain use cases (chat, collaborative editing)
• Auth migration is smooth but requires a password reset for existing users
• Postgres with RLS is more powerful than Firestore Security Rules for complex access control
• Supabase's open-source model and self-hosting option eliminate vendor lock-in entirely
• For new projects in 2026, I default to Supabase unless the use case specifically demands Firestore

All three migrated projects are live in my projects section. More backend and infrastructure posts are on the blog.

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Not affiliated with Supabase or Firebase/Google. Tools used: Supabase CLI, Firebase CLI, pgAdmin, Postman.